1. Field of the Invention
This invention relates to an ink-jet head, an ink-jet cartridge, and an ink-jet printing apparatus using the devices, and an ink-jet printing method, more specifically, applied to ink-jet printing for discharging a printing ink and a print improving liquid for insolubilizing and coagulating a color material in the printing ink.
The present invention can be applied to all types of devices using printing media such as paper, cloth, leather, non-woven fabrics, OHP sheets, metals, or the like. Practical examples of applicable devices include office machines such as printers, copiers, and facsimiles, and industrial production apparatuses.
2. Description of the Prior Art
Heretofore, ink-jet printing method has been utilized in printers and copiers for its low-noise, low running cost, and compact design features, and ease to be applied to color printing.
However, when obtaining an image on a printing material, which is so-called plain paper, by these printing devices using the ink-jet printing method, the image tends to be insufficient in water resistance, and when a color image is obtained, it is impossible to obtain a high-density image with no feathering nor blotting between colors, and a high quality color image with good fastness has not been obtained.
To improve the water resistance of the image, recently an ink containing a water-resistant color material has been practically used. However, its water resistance is yet insufficient, and since the ink in principle becomes water-insoluble after drying, the print head nozzle tends to be clogged, it is insufficient to solve the problem simply by improving the structure of the conventional head or ink-jet printing apparatus, and the apparatus capable of using the print improving liquid tends to be complex in structure.
Further, a number of techniques for improving the fastness of the printed matter have been disclosed. Japanese Patent Application Laid-open No. 24486/1978 discloses a technology in which a dyed matter is treated to convert the dye into a lake for fixing to improve the wet fastness of the dyed matter.
Still further, Japanese Patent Application Laid-open No. 43733/1979 discloses a method using an ink-jet printing system which uses two or more ingredients increasing in film-forming ability at room temperature or when heated, wherein the individual ingredients contact with each other on the printed matter to form a securely fixed film.
Japanese Patent Application Laid-open No. 150396/1980 discloses a method which uses an aqueous dye ink and a water-resistant agent to form a lake with the dye after ink-jet printing.
Yet further, Japanese Patent Application Laid-open No. 128862/1983 discloses an ink-jet printing method in which the position of image to be printed is previously determined and the printing ink and a treatment ink are overlappingly printed, and also discloses a method in which an image is depicted with the treatment ink before the printing ink, the treatment ink is overlapped on the printing ink previously depicted, or the printing ink is overlapped on the previously depicted treatment ink and further depicted with the treatment ink.
However, these patents do not disclose recovery means, head structure, or tank structure for reliability of constructing the ink-jet printing apparatus, nor head structure and print mode for improving the quality of the print image. Further, they do not describe the head structure or printing method for reducing the cost of the printing apparatus, nor printing method for reducing the running cost.
Specifically, the above prior art does not disclose the coating method of the print improving liquid, that is, the coating method by the ink-jet print head in detail, for example, it does not describe a problem of uneven coating due to the coating amount distribution by spray coating over the entire surface before or after printing, and unevenness over time due to a difference in penetration or fixing over time after printing by serial printing specific to ink-jet printing.
The method for printing the treatment ink by ink-jet printing only describes the relationship between the print improving liquid and the ink on the printed image, but does not describe detailed printing method (head structure, print mode, and devices) nor describe problems specific to ink-jet printing occurring in the method.
Any of the above patents does not describe bleeding between colors, bleeding due to difference in ink composition by letter quality and colors to achieve both letter quality and color printing, and white fogging as problems in color printing on plain paper by ink-jet printing, and problems with color printing (color difference due to the application order of color inks: dye distribution in the printing medium) by bidirectional printing to increase the printing speed.
Still further, on the construction of the ink-jet printing apparatus, there is no description of securing the reliability and means for reducing the apparatus cost by simplifying and reducing the structure and device size as possible.
Yet further, there is no description of a printing method for reducing the consumption of the print improving liquid, reducing the running cost, and improving degradation of image quality caused by application position deviation in multibus printing due to cockling.
As described above, with the conventional head structure, it is impossible to reduce the consumption of the print improving liquid, achieve the effect of the print improving liquid, and improve the printing speed in a pre-feed as a combination of a head for the print improving liquid with the conventional printing method (that is, the print improving liquid is applied before the ink), and/or a follow feed (that is, the print improving liquid is applied over the previously applied ink). In particular, it is impossible to forecast the effects of the pre-feed and/or follow feed (penetration control, bleed reduction, reduction of unevenness/stripes), head structure, printing method, and condition of ink immediately after printing (the time to contact of the print improving liquid with colored ink, and penetration condition of the individual ink on the printing medium) and achieve the sufficient effects, and to maintain the effects to an extent, the printing speed must be reduced (including low-speed control of the drive frequency, and temporary interruption of printing), resulting in a reduction of printing throughput.
With a view to solve the above problems, a first object of the present invention is to provide an ink-jet head for optimally utilizing the pre-feed and/or follow feed in ink-jet printing.
A second object of the present invention is to provide a print control method (including image quality improving technique applying head control/image processing) for optimally utilizing the pre-feed and/or follow feed techniques.
Further, a third object of the present invention is to provide an optimal combination of ink (CMY/K/print improving liquid) for optimally utilizing the pre-feed and/or follow feed techniques in ink-jet printing and an ink composition thereof.
Still further, a fourth object of the present invention is to provide an ink-jet printing apparatus which achieves high-precision application of pre-feed and/or follow feed, thereby achieving both high-speed/high quality at a low cost and a low running cost.